537 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
		
		
			
		
	
	
			537 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
|  | /*
 | ||
|  |  *  Portable interface to the CPU cycle counter | ||
|  |  * | ||
|  |  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved | ||
|  |  *  SPDX-License-Identifier: Apache-2.0 | ||
|  |  * | ||
|  |  *  Licensed under the Apache License, Version 2.0 (the "License"); you may | ||
|  |  *  not use this file except in compliance with the License. | ||
|  |  *  You may obtain a copy of the License at | ||
|  |  * | ||
|  |  *  http://www.apache.org/licenses/LICENSE-2.0
 | ||
|  |  * | ||
|  |  *  Unless required by applicable law or agreed to in writing, software | ||
|  |  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT | ||
|  |  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
|  |  *  See the License for the specific language governing permissions and | ||
|  |  *  limitations under the License. | ||
|  |  * | ||
|  |  *  This file is part of mbed TLS (https://tls.mbed.org)
 | ||
|  |  */ | ||
|  | 
 | ||
|  | #if !defined(MBEDTLS_CONFIG_FILE)
 | ||
|  | #include "mbedtls/config.h"
 | ||
|  | #else
 | ||
|  | #include MBEDTLS_CONFIG_FILE
 | ||
|  | #endif
 | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_PLATFORM_C)
 | ||
|  | #include "mbedtls/platform.h"
 | ||
|  | #else
 | ||
|  | #include <stdio.h>
 | ||
|  | #define mbedtls_printf     printf
 | ||
|  | #endif
 | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_TIMING_C)
 | ||
|  | 
 | ||
|  | #include "mbedtls/timing.h"
 | ||
|  | 
 | ||
|  | #if !defined(MBEDTLS_TIMING_ALT)
 | ||
|  | 
 | ||
|  | #if !defined(unix) && !defined(__unix__) && !defined(__unix) && \
 | ||
|  |     !defined(__APPLE__) && !defined(_WIN32) | ||
|  | #error "This module only works on Unix and Windows, see MBEDTLS_TIMING_C in config.h"
 | ||
|  | #endif
 | ||
|  | 
 | ||
|  | #ifndef asm
 | ||
|  | #define asm __asm
 | ||
|  | #endif
 | ||
|  | 
 | ||
|  | #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
 | ||
|  | 
 | ||
|  | #include <windows.h>
 | ||
|  | #include <winbase.h>
 | ||
|  | 
 | ||
|  | struct _hr_time | ||
|  | { | ||
|  |     LARGE_INTEGER start; | ||
|  | }; | ||
|  | 
 | ||
|  | #else
 | ||
|  | 
 | ||
|  | #include <unistd.h>
 | ||
|  | #include <sys/types.h>
 | ||
|  | #include <sys/time.h>
 | ||
|  | #include <signal.h>
 | ||
|  | #include <time.h>
 | ||
|  | 
 | ||
|  | struct _hr_time | ||
|  | { | ||
|  |     struct timeval start; | ||
|  | }; | ||
|  | 
 | ||
|  | #endif /* _WIN32 && !EFIX64 && !EFI32 */
 | ||
|  | 
 | ||
|  | #if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
 | ||
|  |     ( defined(_MSC_VER) && defined(_M_IX86) ) || defined(__WATCOMC__) | ||
|  | 
 | ||
|  | #define HAVE_HARDCLOCK
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_hardclock( void ) | ||
|  | { | ||
|  |     unsigned long tsc; | ||
|  |     __asm   rdtsc | ||
|  |     __asm   mov  [tsc], eax | ||
|  |     return( tsc ); | ||
|  | } | ||
|  | #endif /* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
 | ||
|  |           ( _MSC_VER && _M_IX86 ) || __WATCOMC__ */ | ||
|  | 
 | ||
|  | /* some versions of mingw-64 have 32-bit longs even on x84_64 */ | ||
|  | #if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
 | ||
|  |     defined(__GNUC__) && ( defined(__i386__) || (                       \ | ||
|  |     ( defined(__amd64__) || defined( __x86_64__) ) && __SIZEOF_LONG__ == 4 ) ) | ||
|  | 
 | ||
|  | #define HAVE_HARDCLOCK
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_hardclock( void ) | ||
|  | { | ||
|  |     unsigned long lo, hi; | ||
|  |     asm volatile( "rdtsc" : "=a" (lo), "=d" (hi) ); | ||
|  |     return( lo ); | ||
|  | } | ||
|  | #endif /* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
 | ||
|  |           __GNUC__ && __i386__ */ | ||
|  | 
 | ||
|  | #if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
 | ||
|  |     defined(__GNUC__) && ( defined(__amd64__) || defined(__x86_64__) ) | ||
|  | 
 | ||
|  | #define HAVE_HARDCLOCK
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_hardclock( void ) | ||
|  | { | ||
|  |     unsigned long lo, hi; | ||
|  |     asm volatile( "rdtsc" : "=a" (lo), "=d" (hi) ); | ||
|  |     return( lo | ( hi << 32 ) ); | ||
|  | } | ||
|  | #endif /* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
 | ||
|  |           __GNUC__ && ( __amd64__ || __x86_64__ ) */ | ||
|  | 
 | ||
|  | #if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
 | ||
|  |     defined(__GNUC__) && ( defined(__powerpc__) || defined(__ppc__) ) | ||
|  | 
 | ||
|  | #define HAVE_HARDCLOCK
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_hardclock( void ) | ||
|  | { | ||
|  |     unsigned long tbl, tbu0, tbu1; | ||
|  | 
 | ||
|  |     do | ||
|  |     { | ||
|  |         asm volatile( "mftbu %0" : "=r" (tbu0) ); | ||
|  |         asm volatile( "mftb  %0" : "=r" (tbl ) ); | ||
|  |         asm volatile( "mftbu %0" : "=r" (tbu1) ); | ||
|  |     } | ||
|  |     while( tbu0 != tbu1 ); | ||
|  | 
 | ||
|  |     return( tbl ); | ||
|  | } | ||
|  | #endif /* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
 | ||
|  |           __GNUC__ && ( __powerpc__ || __ppc__ ) */ | ||
|  | 
 | ||
|  | #if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
 | ||
|  |     defined(__GNUC__) && defined(__sparc64__) | ||
|  | 
 | ||
|  | #if defined(__OpenBSD__)
 | ||
|  | #warning OpenBSD does not allow access to tick register using software version instead
 | ||
|  | #else
 | ||
|  | #define HAVE_HARDCLOCK
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_hardclock( void ) | ||
|  | { | ||
|  |     unsigned long tick; | ||
|  |     asm volatile( "rdpr %%tick, %0;" : "=&r" (tick) ); | ||
|  |     return( tick ); | ||
|  | } | ||
|  | #endif /* __OpenBSD__ */
 | ||
|  | #endif /* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
 | ||
|  |           __GNUC__ && __sparc64__ */ | ||
|  | 
 | ||
|  | #if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
 | ||
|  |     defined(__GNUC__) && defined(__sparc__) && !defined(__sparc64__) | ||
|  | 
 | ||
|  | #define HAVE_HARDCLOCK
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_hardclock( void ) | ||
|  | { | ||
|  |     unsigned long tick; | ||
|  |     asm volatile( ".byte 0x83, 0x41, 0x00, 0x00" ); | ||
|  |     asm volatile( "mov   %%g1, %0" : "=r" (tick) ); | ||
|  |     return( tick ); | ||
|  | } | ||
|  | #endif /* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
 | ||
|  |           __GNUC__ && __sparc__ && !__sparc64__ */ | ||
|  | 
 | ||
|  | #if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&      \
 | ||
|  |     defined(__GNUC__) && defined(__alpha__) | ||
|  | 
 | ||
|  | #define HAVE_HARDCLOCK
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_hardclock( void ) | ||
|  | { | ||
|  |     unsigned long cc; | ||
|  |     asm volatile( "rpcc %0" : "=r" (cc) ); | ||
|  |     return( cc & 0xFFFFFFFF ); | ||
|  | } | ||
|  | #endif /* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
 | ||
|  |           __GNUC__ && __alpha__ */ | ||
|  | 
 | ||
|  | #if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&      \
 | ||
|  |     defined(__GNUC__) && defined(__ia64__) | ||
|  | 
 | ||
|  | #define HAVE_HARDCLOCK
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_hardclock( void ) | ||
|  | { | ||
|  |     unsigned long itc; | ||
|  |     asm volatile( "mov %0 = ar.itc" : "=r" (itc) ); | ||
|  |     return( itc ); | ||
|  | } | ||
|  | #endif /* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
 | ||
|  |           __GNUC__ && __ia64__ */ | ||
|  | 
 | ||
|  | #if !defined(HAVE_HARDCLOCK) && defined(_MSC_VER) && \
 | ||
|  |     !defined(EFIX64) && !defined(EFI32) | ||
|  | 
 | ||
|  | #define HAVE_HARDCLOCK
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_hardclock( void ) | ||
|  | { | ||
|  |     LARGE_INTEGER offset; | ||
|  | 
 | ||
|  |     QueryPerformanceCounter( &offset ); | ||
|  | 
 | ||
|  |     return( (unsigned long)( offset.QuadPart ) ); | ||
|  | } | ||
|  | #endif /* !HAVE_HARDCLOCK && _MSC_VER && !EFIX64 && !EFI32 */
 | ||
|  | 
 | ||
|  | #if !defined(HAVE_HARDCLOCK)
 | ||
|  | 
 | ||
|  | #define HAVE_HARDCLOCK
 | ||
|  | 
 | ||
|  | static int hardclock_init = 0; | ||
|  | static struct timeval tv_init; | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_hardclock( void ) | ||
|  | { | ||
|  |     struct timeval tv_cur; | ||
|  | 
 | ||
|  |     if( hardclock_init == 0 ) | ||
|  |     { | ||
|  |         gettimeofday( &tv_init, NULL ); | ||
|  |         hardclock_init = 1; | ||
|  |     } | ||
|  | 
 | ||
|  |     gettimeofday( &tv_cur, NULL ); | ||
|  |     return( ( tv_cur.tv_sec  - tv_init.tv_sec  ) * 1000000 | ||
|  |           + ( tv_cur.tv_usec - tv_init.tv_usec ) ); | ||
|  | } | ||
|  | #endif /* !HAVE_HARDCLOCK */
 | ||
|  | 
 | ||
|  | volatile int mbedtls_timing_alarmed = 0; | ||
|  | 
 | ||
|  | #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset ) | ||
|  | { | ||
|  |     struct _hr_time *t = (struct _hr_time *) val; | ||
|  | 
 | ||
|  |     if( reset ) | ||
|  |     { | ||
|  |         QueryPerformanceCounter( &t->start ); | ||
|  |         return( 0 ); | ||
|  |     } | ||
|  |     else | ||
|  |     { | ||
|  |         unsigned long delta; | ||
|  |         LARGE_INTEGER now, hfreq; | ||
|  |         QueryPerformanceCounter(  &now ); | ||
|  |         QueryPerformanceFrequency( &hfreq ); | ||
|  |         delta = (unsigned long)( ( now.QuadPart - t->start.QuadPart ) * 1000ul | ||
|  |                                  / hfreq.QuadPart ); | ||
|  |         return( delta ); | ||
|  |     } | ||
|  | } | ||
|  | 
 | ||
|  | /* It's OK to use a global because alarm() is supposed to be global anyway */ | ||
|  | static DWORD alarmMs; | ||
|  | 
 | ||
|  | static DWORD WINAPI TimerProc( LPVOID TimerContext ) | ||
|  | { | ||
|  |     ((void) TimerContext); | ||
|  |     Sleep( alarmMs ); | ||
|  |     mbedtls_timing_alarmed = 1; | ||
|  |     return( TRUE ); | ||
|  | } | ||
|  | 
 | ||
|  | void mbedtls_set_alarm( int seconds ) | ||
|  | { | ||
|  |     DWORD ThreadId; | ||
|  | 
 | ||
|  |     if( seconds == 0 ) | ||
|  |     { | ||
|  |         /* No need to create a thread for this simple case.
 | ||
|  |          * Also, this shorcut is more reliable at least on MinGW32 */ | ||
|  |         mbedtls_timing_alarmed = 1; | ||
|  |         return; | ||
|  |     } | ||
|  | 
 | ||
|  |     mbedtls_timing_alarmed = 0; | ||
|  |     alarmMs = seconds * 1000; | ||
|  |     CloseHandle( CreateThread( NULL, 0, TimerProc, NULL, 0, &ThreadId ) ); | ||
|  | } | ||
|  | 
 | ||
|  | #else /* _WIN32 && !EFIX64 && !EFI32 */
 | ||
|  | 
 | ||
|  | unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset ) | ||
|  | { | ||
|  |     struct _hr_time *t = (struct _hr_time *) val; | ||
|  | 
 | ||
|  |     if( reset ) | ||
|  |     { | ||
|  |         gettimeofday( &t->start, NULL ); | ||
|  |         return( 0 ); | ||
|  |     } | ||
|  |     else | ||
|  |     { | ||
|  |         unsigned long delta; | ||
|  |         struct timeval now; | ||
|  |         gettimeofday( &now, NULL ); | ||
|  |         delta = ( now.tv_sec  - t->start.tv_sec  ) * 1000ul | ||
|  |               + ( now.tv_usec - t->start.tv_usec ) / 1000; | ||
|  |         return( delta ); | ||
|  |     } | ||
|  | } | ||
|  | 
 | ||
|  | static void sighandler( int signum ) | ||
|  | { | ||
|  |     mbedtls_timing_alarmed = 1; | ||
|  |     signal( signum, sighandler ); | ||
|  | } | ||
|  | 
 | ||
|  | void mbedtls_set_alarm( int seconds ) | ||
|  | { | ||
|  |     mbedtls_timing_alarmed = 0; | ||
|  |     signal( SIGALRM, sighandler ); | ||
|  |     alarm( seconds ); | ||
|  |     if( seconds == 0 ) | ||
|  |     { | ||
|  |         /* alarm(0) cancelled any previous pending alarm, but the
 | ||
|  |            handler won't fire, so raise the flag straight away. */ | ||
|  |         mbedtls_timing_alarmed = 1; | ||
|  |     } | ||
|  | } | ||
|  | 
 | ||
|  | #endif /* _WIN32 && !EFIX64 && !EFI32 */
 | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Set delays to watch | ||
|  |  */ | ||
|  | void mbedtls_timing_set_delay( void *data, uint32_t int_ms, uint32_t fin_ms ) | ||
|  | { | ||
|  |     mbedtls_timing_delay_context *ctx = (mbedtls_timing_delay_context *) data; | ||
|  | 
 | ||
|  |     ctx->int_ms = int_ms; | ||
|  |     ctx->fin_ms = fin_ms; | ||
|  | 
 | ||
|  |     if( fin_ms != 0 ) | ||
|  |         (void) mbedtls_timing_get_timer( &ctx->timer, 1 ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Get number of delays expired | ||
|  |  */ | ||
|  | int mbedtls_timing_get_delay( void *data ) | ||
|  | { | ||
|  |     mbedtls_timing_delay_context *ctx = (mbedtls_timing_delay_context *) data; | ||
|  |     unsigned long elapsed_ms; | ||
|  | 
 | ||
|  |     if( ctx->fin_ms == 0 ) | ||
|  |         return( -1 ); | ||
|  | 
 | ||
|  |     elapsed_ms = mbedtls_timing_get_timer( &ctx->timer, 0 ); | ||
|  | 
 | ||
|  |     if( elapsed_ms >= ctx->fin_ms ) | ||
|  |         return( 2 ); | ||
|  | 
 | ||
|  |     if( elapsed_ms >= ctx->int_ms ) | ||
|  |         return( 1 ); | ||
|  | 
 | ||
|  |     return( 0 ); | ||
|  | } | ||
|  | 
 | ||
|  | #endif /* !MBEDTLS_TIMING_ALT */
 | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_SELF_TEST)
 | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Busy-waits for the given number of milliseconds. | ||
|  |  * Used for testing mbedtls_timing_hardclock. | ||
|  |  */ | ||
|  | static void busy_msleep( unsigned long msec ) | ||
|  | { | ||
|  |     struct mbedtls_timing_hr_time hires; | ||
|  |     unsigned long i = 0; /* for busy-waiting */ | ||
|  |     volatile unsigned long j; /* to prevent optimisation */ | ||
|  | 
 | ||
|  |     (void) mbedtls_timing_get_timer( &hires, 1 ); | ||
|  | 
 | ||
|  |     while( mbedtls_timing_get_timer( &hires, 0 ) < msec ) | ||
|  |         i++; | ||
|  | 
 | ||
|  |     j = i; | ||
|  |     (void) j; | ||
|  | } | ||
|  | 
 | ||
|  | #define FAIL    do                                                      \
 | ||
|  |     {                                                                   \ | ||
|  |         if( verbose != 0 )                                              \ | ||
|  |         {                                                               \ | ||
|  |             mbedtls_printf( "failed at line %d\n", __LINE__ );          \ | ||
|  |             mbedtls_printf( " cycles=%lu ratio=%lu millisecs=%lu secs=%lu hardfail=%d a=%lu b=%lu\n", \ | ||
|  |                             cycles, ratio, millisecs, secs, hardfail,   \ | ||
|  |                             (unsigned long) a, (unsigned long) b );     \ | ||
|  |             mbedtls_printf( " elapsed(hires)=%lu elapsed(ctx)=%lu status(ctx)=%d\n", \ | ||
|  |                             mbedtls_timing_get_timer( &hires, 0 ),      \ | ||
|  |                             mbedtls_timing_get_timer( &ctx.timer, 0 ),  \ | ||
|  |                             mbedtls_timing_get_delay( &ctx ) );         \ | ||
|  |         }                                                               \ | ||
|  |         return( 1 );                                                    \ | ||
|  |     } while( 0 ) | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Checkup routine | ||
|  |  * | ||
|  |  * Warning: this is work in progress, some tests may not be reliable enough | ||
|  |  * yet! False positives may happen. | ||
|  |  */ | ||
|  | int mbedtls_timing_self_test( int verbose ) | ||
|  | { | ||
|  |     unsigned long cycles = 0, ratio = 0; | ||
|  |     unsigned long millisecs = 0, secs = 0; | ||
|  |     int hardfail = 0; | ||
|  |     struct mbedtls_timing_hr_time hires; | ||
|  |     uint32_t a = 0, b = 0; | ||
|  |     mbedtls_timing_delay_context ctx; | ||
|  | 
 | ||
|  |     if( verbose != 0 ) | ||
|  |         mbedtls_printf( "  TIMING tests note: will take some time!\n" ); | ||
|  | 
 | ||
|  |     if( verbose != 0 ) | ||
|  |         mbedtls_printf( "  TIMING test #1 (set_alarm / get_timer): " ); | ||
|  | 
 | ||
|  |     { | ||
|  |         secs = 1; | ||
|  | 
 | ||
|  |         (void) mbedtls_timing_get_timer( &hires, 1 ); | ||
|  | 
 | ||
|  |         mbedtls_set_alarm( (int) secs ); | ||
|  |         while( !mbedtls_timing_alarmed ) | ||
|  |             ; | ||
|  | 
 | ||
|  |         millisecs = mbedtls_timing_get_timer( &hires, 0 ); | ||
|  | 
 | ||
|  |         /* For some reason on Windows it looks like alarm has an extra delay
 | ||
|  |          * (maybe related to creating a new thread). Allow some room here. */ | ||
|  |         if( millisecs < 800 * secs || millisecs > 1200 * secs + 300 ) | ||
|  |             FAIL; | ||
|  |     } | ||
|  | 
 | ||
|  |     if( verbose != 0 ) | ||
|  |         mbedtls_printf( "passed\n" ); | ||
|  | 
 | ||
|  |     if( verbose != 0 ) | ||
|  |         mbedtls_printf( "  TIMING test #2 (set/get_delay        ): " ); | ||
|  | 
 | ||
|  |     { | ||
|  |         a = 800; | ||
|  |         b = 400; | ||
|  |         mbedtls_timing_set_delay( &ctx, a, a + b );          /* T = 0 */ | ||
|  | 
 | ||
|  |         busy_msleep( a - a / 4 );                      /* T = a - a/4 */ | ||
|  |         if( mbedtls_timing_get_delay( &ctx ) != 0 ) | ||
|  |             FAIL; | ||
|  | 
 | ||
|  |         busy_msleep( a / 4 + b / 4 );                  /* T = a + b/4 */ | ||
|  |         if( mbedtls_timing_get_delay( &ctx ) != 1 ) | ||
|  |             FAIL; | ||
|  | 
 | ||
|  |         busy_msleep( b );                          /* T = a + b + b/4 */ | ||
|  |         if( mbedtls_timing_get_delay( &ctx ) != 2 ) | ||
|  |             FAIL; | ||
|  |     } | ||
|  | 
 | ||
|  |     mbedtls_timing_set_delay( &ctx, 0, 0 ); | ||
|  |     busy_msleep( 200 ); | ||
|  |     if( mbedtls_timing_get_delay( &ctx ) != -1 ) | ||
|  |         FAIL; | ||
|  | 
 | ||
|  |     if( verbose != 0 ) | ||
|  |         mbedtls_printf( "passed\n" ); | ||
|  | 
 | ||
|  |     if( verbose != 0 ) | ||
|  |         mbedtls_printf( "  TIMING test #3 (hardclock / get_timer): " ); | ||
|  | 
 | ||
|  |     /*
 | ||
|  |      * Allow one failure for possible counter wrapping. | ||
|  |      * On a 4Ghz 32-bit machine the cycle counter wraps about once per second; | ||
|  |      * since the whole test is about 10ms, it shouldn't happen twice in a row. | ||
|  |      */ | ||
|  | 
 | ||
|  | hard_test: | ||
|  |     if( hardfail > 1 ) | ||
|  |     { | ||
|  |         if( verbose != 0 ) | ||
|  |             mbedtls_printf( "failed (ignored)\n" ); | ||
|  | 
 | ||
|  |         goto hard_test_done; | ||
|  |     } | ||
|  | 
 | ||
|  |     /* Get a reference ratio cycles/ms */ | ||
|  |     millisecs = 1; | ||
|  |     cycles = mbedtls_timing_hardclock(); | ||
|  |     busy_msleep( millisecs ); | ||
|  |     cycles = mbedtls_timing_hardclock() - cycles; | ||
|  |     ratio = cycles / millisecs; | ||
|  | 
 | ||
|  |     /* Check that the ratio is mostly constant */ | ||
|  |     for( millisecs = 2; millisecs <= 4; millisecs++ ) | ||
|  |     { | ||
|  |         cycles = mbedtls_timing_hardclock(); | ||
|  |         busy_msleep( millisecs ); | ||
|  |         cycles = mbedtls_timing_hardclock() - cycles; | ||
|  | 
 | ||
|  |         /* Allow variation up to 20% */ | ||
|  |         if( cycles / millisecs < ratio - ratio / 5 || | ||
|  |             cycles / millisecs > ratio + ratio / 5 ) | ||
|  |         { | ||
|  |             hardfail++; | ||
|  |             goto hard_test; | ||
|  |         } | ||
|  |     } | ||
|  | 
 | ||
|  |     if( verbose != 0 ) | ||
|  |         mbedtls_printf( "passed\n" ); | ||
|  | 
 | ||
|  | hard_test_done: | ||
|  | 
 | ||
|  |     if( verbose != 0 ) | ||
|  |         mbedtls_printf( "\n" ); | ||
|  | 
 | ||
|  |     return( 0 ); | ||
|  | } | ||
|  | 
 | ||
|  | #endif /* MBEDTLS_SELF_TEST */
 | ||
|  | 
 | ||
|  | #endif /* MBEDTLS_TIMING_C */
 |